Internal values of Combobox, Listbox

[M[a]nny]

Hello.

Imagine MySQL database with one table which contains these columns: "UserId, UserName".
Now, we want to fill Combobox with all users in database ordered by their names.

Code: [Select]

Combobox.Clear;
Query.SQL.Text := 'SELECT * FROM users';
Query.Open;
while not Query.EOF then begin
  Combobox.Items.Add(Query.FieldByName('UserName').AsString);
  Query.Next;
end;
Query.Close;

All users are showed in items of Combobox. And the problem is... how can I recognize ID of the selected user? I can't do it by his name because of duplicate rows. Is there any way to do this easy? Thanks for helping.

[Marc]

Maybe have a look at the TDBLookupCombobox.

But if you want a standalone Combobox, you can "store" the ID in the object part (this is a bit of a hack)

Code: Pascal  [Select][+][-]

1. Combobox.Clear;
2. Query.SQL.Text := 'SELECT * FROM users';
3. Query.Open;
4. while not Query.EOF do
5. begin
6.   Combobox.Items.AddObject(Query.FieldByName('UserName').AsString, TObject(Query.FieldByName('ID').AsInteger));
7.   Query.Next;
8. end;
9. Query.Close;
10.  

btw, if you only need ID and Username, then selecting "select id,username form..." is more efficient

[M[a]nny]

Thank you for your time and experience.
I made it by this way:

If i want to add new item to ComboBox:

Code: Pascal  [Select][+][-]

1. UsrName := 'Chuck Norris'; // type: string
2. UsrID := 1; // type: integer
3. ComboBox.Items.AddObject(UsrName, TObject(UsrID));

... and if I want to check what object is selected (returns UsrID):

Code: Pascal  [Select][+][-]

1. SelectedID := Integer(ComboBox.Items.Objects[ComboBox.ItemIndex]); // type: integer

[xinyiman]

Prova a seguire questo link, sono due componenti che ho fatto io. Si possono visualizzare anche più campi oltre ad avere un campo chiave nascosto.

Ha solo un piccolo difetto la combobox, quando si cercano di visualizzare più campi non riesco a incolonnarli perchè non riesco a definire il formato del testo nel popup che ti visualizza i dati disponibili per essere selezionati.

http://www.lazarus.freepascal.org/index.php?topic=8708.0

edit:
replaced ip by address